Thanks for reply Partrick, but I'm a bit lost.
My device, in this case a USB drive plugged into the host, doesn't seem to be found at all in Workstation, so I'm not sure how I can attempt to mount it manually. There is no sign of a USB in the Removable Media menu. So, I'm not sure if this is a case of the "auto mounter" vs. manual mount- it seems there's something more basic wrong? Am I correct I should be able to "see" the unmounted USB in Workstation to start the process of manually mounting it?
I tried the instructions in forum topic 1526. I installed Gparted on Workstation, but again no sign of the USB in Gparted.
So, I'm stuck at the moment